1. Field of the Invention
The invention relates to a fuel supply device and a fuel supply method for an internal combustion engine.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-A-2004-84560 discloses a fuel supply device for an internal combustion engine in which the fuel drawn up from a fuel tank by a low-pressure fuel pump is pressurized and fed to a delivery pipe by a high-pressure fuel pump, and the fuel in the delivery pipe is supplied into combustion chambers via injectors. When the internal combustion engine is about to be stopped, this fuel supply device stops the high-pressure fuel pump but continues the injecting operation of the injectors and the operation of the low-pressure pump to lower the pressure of fuel in the delivery pipe so that leakage of fuel from the injectors is curbed during the period of the stop of the internal combustion engine. Another related-art document relevant to the invention is Japanese Patent Application Publication No. JP-A-9-151827.
According to the aforementioned device of Japanese Patent Application Publication No. JP-A-2004-84560, the fuel injection into the combustion chambers and the combustion of injected fuel are continued during a period from the occurrence of a stop signal for the internal combustion engine in response to the turning-off of the ignition key until the pressure in the delivery pipe (hereinafter, sometimes referred to as “pressure accumulator”) drops. Therefore, there is risk of giving a driver an awkward impression that the internal combustion engine continues operating when the driver has turned off the ignition key. Japanese Patent Application Publication No. JP-A-9-151827 mentioned above does not disclose a control of the pressure in the delivery pipe at the time of stopping the internal combustion engine.